U.S. patent application number 09/902559 was filed with the patent office on 2003-01-16 for remote pumping of optical amplifier system and method.
Invention is credited to Maas, Steven J..
Application Number | 20030011878 09/902559 |
Document ID | / |
Family ID | 25416021 |
Filed Date | 2003-01-16 |
United States Patent
Application |
20030011878 |
Kind Code |
A1 |
Maas, Steven J. |
January 16, 2003 |
Remote pumping of optical amplifier system and method
Abstract
Several embodiments of an apparatus for remote amplification of
seismic sensor fiber optical signals from seismic sensor arrays are
disclosed. The seismic sensor fiber optical signals are transmitted
using FDM/WDM and TDM/WDM techniques. Embodiments of the invention
allow for modular structure of the seismic sensor arrays, wherein
the excess of the pumped optical energy is used to amplify another
module of the sensor arrays. The sensor arrays can be arranged in
serial and/or parallel configuration. An embodiment of the
invention allows for repeated amplification of the seismic sensor
fiber optical signals using pumped optical energy from a single
source. In another aspect of the invention, systems corresponding
to the apparatus and methods of using the systems are
disclosed.
Inventors: |
Maas, Steven J.; (Austin,
TX) |
Correspondence
Address: |
PGS Americas Inc
16010 Baker's Point Lane
Suite 300
Houston
TX
77079
US
|
Family ID: |
25416021 |
Appl. No.: |
09/902559 |
Filed: |
July 11, 2001 |
Current U.S.
Class: |
359/341.3 |
Current CPC
Class: |
H01S 3/06758 20130101;
H01S 3/094003 20130101 |
Class at
Publication: |
359/341.3 |
International
Class: |
H01S 003/00 |
Claims
What is claimed is:
1. An apparatus for remote amplification of at least one optical
sensor signal, the apparatus comprising at least one amplification
section, the at least one amplification section comprising: a first
wavelength-selective coupler having a first coupler first side and
a first coupler second side, the first coupler first side further
comprising an optical pump input port adapted to receive an optical
pump input, and a signal output port adapted to output an amplified
optical sensor signal, and the first coupler second side having a
first coupler optical amplifier connection port; an optical
amplifier comprising an amplifier first port and an amplifier
second port, wherein the amplifier first port is coupled to the
first coupler optical amplifier connection port; and a second
wavelength-selective coupler having a second coupler first side and
a second coupler second side, the second coupler first side
optically coupled to the amplifier second port, and the second
coupler second side further comprising a second coupler signal
input port and an optical pump tap out port, wherein the second
coupler signal input port is adapted to receive one of the at least
one optical sensor signal input, and the optical pump tap out port
is adapted to output an excess optical pump energy to another
amplification section.
2. An apparatus as in claim 1, wherein the at least one
amplification section comprises a plurality of amplification
sections, wherein each amplification section is adapted to receive
one optical sensor signal input, output one optical sensor signal
output and output one excess optical pump energy to an adjacent
amplification section.
3. An apparatus as in claim 1, wherein the first
wavelength-selective coupler comprises a WDM coupler.
4. An apparatus as in claim 1, wherein the second
wavelength-selective coupler comprises a WDM coupler.
5. An apparatus as in claim 1, wherein the optical amplifier
comprises an erbium doped optical amplifier.
6. An apparatus as in claim 1, wherein the second coupler signal
input port further comprises an optical isolator.
7. An apparatus as in claim 6, wherein the optical isolator is
integral to the second coupler signal input port.
8. An apparatus as in claim 1 wherein the optical sensor signal
comprises a seismic optical sensor signal, and the amplified sensor
optical signal comprises an amplified seismic optical sensor
signal.
9. An apparatus for remote multistage amplification of a optical
sensor signal, the apparatus comprising: a first
wavelength-selective coupler having a first coupler first side and
a first coupler second side, wherein the first coupler first side
further comprises a first coupler optical pump input port adapted
to receive an optical pump input, and a first coupler signal output
port adapted to output an amplified optical sensor signal, and the
first coupler second side having a first coupler optical amplifier
connection port; a first optical amplifier having a first amplifier
first port and a first amplifier second port, wherein the first
amplifier first port is coupled to the first coupler optical
amplifier connection port; a second wavelength-selective coupler
having a second coupler first side and a second coupler second
side, wherein the second coupler first side is optically coupled to
the first amplifier second port, and the second coupler second side
further comprises a second coupler signal input port and a second
coupler optical pump output port, wherein the second coupler signal
input port is adapted to receive an amplified optical sensor signal
input, and the second coupler optical pump output port is adapted
to output a first excess optical pump energy; a third
wavelength-selective coupler having a third coupler first side and
a third coupler second side, wherein the third coupler first side
further comprises a third coupler signal output port, and a third
coupler optical pump energy input port, and wherein the third
coupler optical pump energy input port optically coupled to the
second coupler optical pump output port, and the third coupler
second side further comprising a third coupler signal input port; a
second optical amplifier having a second amplifier first port and a
second amplifier second port, wherein the second amplifier first
port is coupled to the third coupler signal input port; and a
fourth wavelength-selective coupler having a fourth coupler first
side and a fourth coupler second side, wherein the fourth coupler
first side is optically coupled to the second amplifier second
port, and the fourth coupler second side further comprises a fourth
coupler signal input port and a fourth coupler optical pump output
port, wherein the fourth coupler signal input port is adapted to
receive a optical sensor signal input, and the fourth coupler
optical pump output port is adapted to output a second excess
optical pump energy.
10. An apparatus as in claim 9, wherein the first
wavelength-selective coupler comprises a WDM coupler.
11. An apparatus as in claim 9, wherein the first optical amplifier
comprises an erbium doped optical amplifier.
12. An apparatus as in claim 9, wherein the second
wavelength-selective coupler comprises a WDM coupler.
13. An apparatus as in claim 9, wherein the second coupler signal
input port further comprises a first optical isolator.
14. An apparatus as in claim 13, wherein the first optical isolator
is integral to the second coupler signal input port.
15. An apparatus as in claim 9, wherein the third
wavelength-selective coupler comprises a WDM coupler.
16. An apparatus as in claim 9, wherein the second optical
amplifier comprises an erbium doped optical amplifier.
17. An apparatus as in claim 9, wherein the fourth
wavelength-selective coupler comprises a WDM coupler.
18. An apparatus as in claim 9, wherein the fourth coupler signal
input port further comprises a second optical isolator.
19. An apparatus as in claim 18, wherein the second optical
isolator is integral to the fourth coupler signal input port.
20. An apparatus for remote amplification of a plurality of optical
sensor signals in a parallel configuration using an optical pump,
the apparatus comprising: a first wavelength-selective coupler
having a first coupler first side and a first coupler second side,
wherein the first coupler first side further comprises a first
coupler optical pump input port coupled to an optical pump, and a
first coupler signal output port adapted to output a first
amplified optical sensor signal, and the first coupler second side
having a first coupler optical amplifier connection port; a first
optical amplifier having a first amplifier first port and a first
amplifier second port, wherein the first amplifier first port is
coupled to the first coupler optical amplifier connection port, and
the first amplifier second port adapted to receive a first optical
sensor signal input; a second wavelength-selective coupler having a
second coupler first side and a second coupler second side, wherein
the second coupler first side further comprises a second coupler
optical pump input port coupled to the optical pump, and a second
coupler signal output port adapted to output a second amplified
optical sensor signal, and the second coupler second side having a
second coupler optical amplifier connection port; and a second
optical amplifier having a second amplifier first port and a second
amplifier second port, wherein the second amplifier first port is
coupled to the second coupler optical amplifier connection port,
and the second amplifier second port adapted to receive a second
optical sensor signal input.
21. An apparatus as in claim 20, wherein the first
wavelength-selective coupler comprises a WDM coupler.
22. An apparatus as in claim 20, wherein the first optical
amplifier comprises an erbium doped optical amplifier.
23. An apparatus as in claim 20, wherein the first amplifier second
port further comprises a first optical isolator.
24. An apparatus as in claim 23, wherein the first optical isolator
is integral to the first amplifier second port.
25. An apparatus as in claim 20, wherein the second
wavelength-selective coupler comprises a WDM coupler.
26. An apparatus as in claim 20, wherein the second optical
amplifier comprises an erbium doped optical amplifier.
27. An apparatus as in claim 20, wherein the second amplifier
second port further comprises a second optical isolator.
28. An apparatus as in claim 27, wherein the second optical
isolator is integral to the second amplifier second port.
29. A method for amplifying optical sensor signals, the method
comprising: pumping a first optical amplifier, located in a seismic
cable, with a pumping source; feeding a first optical signal to the
first optical amplifier; pumping a second optical amplifier,
located in the seismic cable, with the pumping source; and feeding
a second optical signal to the second optical amplifier.
30. The method of claim 29, wherein the feeding the first optical
signal comprises through a first telemetry line, and the feeding
the second optical signal comprises through a second telemetry
line.
31. The method of claim 29, wherein the method further comprises
splitting a pump signal from the pumping source before the pumping
the first optical amplifiers and before the pumping the second
optical amplifier.
32. The method of claim 29, wherein the method further comprises
receiving the first optical signal from a first seismic sensor
array section, and receiving the second optical signal from a
second seismic sensor array section.
33. The method of claim 29, wherein the method further comprises
pumping additional optical amplifiers with the pumping source.
34. The method of claim 29, wherein the method further comprises
feeding additional optical signals to additional optical
amplifiers.
35. The method of claim 34, wherein the feeding additional optical
signals comprises through separate telemetry lines.
36. A system for amplifying optical sensor signals, the system
comprising: means for pumping a first optical amplifier, located in
a seismic cable, with a pumping source; means for feeding a first
optical signal to the first optical amplifier; means for pumping a
second optical amplifier, located in the seismic cable, with the
pumping source; and means for feeding a second optical signal to
the second optical amplifier.
37. The system of claim 36, wherein the means for feeding the first
optical signal comprises through a first telemetry line, and the
means for feeding the second optical signal comprises through a
second telemetry line.
38. The system of claim 36, wherein the system further comprises
means for splitting a pump signal from the pumping source before
the means for pumping the first optical amplifiers and before the
means for pumping the second optical amplifier.
39. The system of claim 36, wherein the system further comprises
means for receiving the first optical signal from a first seismic
sensor array, and means for receiving the second optical signal
from a second seismic sensor array.
40. The system of claim 36, wherein the system further comprises
means for pumping additional optical amplifiers with the pumping
source.
41. The system of claim 36, wherein the system further comprises
means for feeding additional optical signals to additional optical
amplifiers.
42. The system of claim 41, wherein the means for feeding
additional optical signals comprises through separate telemetry
lines.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to optical amplifiers and
specifically to fiber optic telemetry systems and methods.
[0002] In a typical configuration for an optical amplifier, an
optical signal feeds a piece of doped optical fiber, the dopant
ions in the fiber being excited by a pump signal into the fiber. As
the signal enters the amplifier, the energy from the excited dopant
ions is transferred into photons at the signal wavelength. In
addition, in many typical configurations the signal for the optical
amplifiers is sent with circulators integral to the amplifier. In
such amplifier configurations, however, individual pump diodes are
resident at each optical amplifier.
[0003] Seismic sensor arrays typically extend over long distances,
sometimes several miles. An economic approach to sensing the
seismic arrays is through fiber optic telemetry schemes. Many
times, however, the optical loss associated with these telemetry
schemes is excessive and results in a problem regarding optical
signal attenuation. That is, optical signal attenuation may become
significant over long distances, and the signal requires optical
amplifiers to make up for the propagation signal loss. Multiple
stages of amplification are added to accommodate all of the fibers
in an array along the signal path in order to increase the signal
to noise ratio. In addition, to achieve multiple amplifications,
conventional practice requires an individual pump diode resident at
each amplifier.
[0004] Accordingly, there is a need for a system and method for
amplifying a signal that avoids the need for individual pump diodes
at each optical amplifier. It is an object of the present invention
to address the above-described needs.
SUMMARY OF THE INVENTION
[0005] The above needs are addressed, according to one example
embodiment of the invention, by providing an amplification method
and system that uses remote optical pumping of multiple stages of
amplification with a single pump line. In some embodiments, a
single pump fiber is used with multiple amplifiers on many
telemetry lines. In other embodiments, multiple amplifiers are used
on a single telemetry line.
[0006] In one aspect of the invention, a method is provided for
amplifying optical sensor signals, the method comprising: pumping a
first optical amplifier, located in a seismic cable, with a pumping
source; feeding a first optical signal to the first optical
amplifier; pumping a second optical amplifier, located in the
seismic cable, with the pumping source; and feeding a second
optical signal to the second optical amplifier.
[0007] In another of the invention, a system is provided for
amplifying optical sensor signals, the system comprising: means for
pumping a first optical amplifier, located in a seismic cable, with
a pumping source; means for feeding a first optical signal to the
first optical amplifier; means for pumping a second optical
amplifier, located in the seismic cable, with the pumping source;
and means for feeding a second optical signal to the second optical
amplifier.
[0008] In a further aspect of the invention, an apparatus for
remote amplification of at least one optical sensor signal is
provided. In one example embodiment, the apparatus comprises at
least one amplification section, wherein the at least one
amplification section comprises a first wavelength-selective
coupler having a first coupler first side and a first coupler
second side, the first coupler first side further comprising an
optical pump input port adapted to receive an optical pump input,
and a signal output port adapted to output an amplified optical
sensor signal, and the first coupler second side having a first
coupler optical amplifier connection port. The apparatus further
comprises an optical amplifier having an amplifier first port and
an amplifier second port, wherein the amplifier first port is
coupled to the first coupler optical amplifier connection port.
Further still, the apparatus comprises a second
wavelength-selective coupler having a second coupler first side and
a second coupler second side, the second coupler first side
optically coupled to the amplifier second port, and the second
coupler second side further comprising a second coupler signal
input port and an optical pump tap out port, wherein the second
coupler signal input port is adapted to receive one of the at least
one optical sensor signal input, and the optical pump tap out port
is adapted to output an excess optical pump energy to another
amplification section.
[0009] According to another aspect of the present invention, an
apparatus for remote multistage amplification of a optical sensor
signal is provided. In one example embodiment, the apparatus
comprises a first wavelength-selective coupler having a first
coupler first side and a first coupler second side, wherein the
first coupler first side further comprising a first coupler optical
pump input port adapted to receive an optical pump input, and a
first coupler signal output port adapted to output an amplified
optical sensor signal, and the first coupler second side having a
first coupler optical amplifier connection port; a first optical
amplifier having a first amplifier first port and a first amplifier
second port, wherein the first amplifier first port is coupled to
the first coupler optical amplifier connection port. The apparatus
further comprises a second wavelength-selective coupler having a
second coupler first side and a second coupler second side, wherein
the second coupler first side is optically coupled to the first
amplifier second port, and the second coupler second side further
comprising a second coupler signal input port and a second coupler
optical pump output port, wherein the second coupler signal input
port is adapted to receive an amplified optical sensor signal
input, and the second coupler optical pump output port is adapted
to output a first excess optical pump energy. The apparatus further
comprises a third wavelength-selective coupler having a third
coupler first side and a third coupler second side, wherein the
third coupler first side further comprising a third coupler signal
output port, and a third coupler optical pump energy input port,
and wherein the third coupler optical pump energy input port
optically coupled to the second coupler optical pump output port,
and the third coupler second side further comprising a third
coupler signal input port; a second optical amplifier having a
second amplifier first port and a second amplifier second port,
wherein the second amplifier first port is coupled to the third
coupler signal input port. Further still, the apparatus comprises a
fourth wavelength-selective coupler having a fourth coupler first
side and a fourth coupler second side, wherein the fourth coupler
first side is optically coupled to the second amplifier second
port, and the fourth coupler second side further comprising a
fourth coupler signal input port and a fourth coupler optical pump
output port, wherein the fourth coupler signal input port is
adapted to receive a optical sensor signal input, and the fourth
coupler optical pump output port is adapted to output a second
excess optical pump energy.
[0010] According to still another aspect of the present invention,
an apparatus for remote amplification a plurality of optical sensor
signals in a parallel configuration using an optical pump is
provided. In an example embodiment, the apparatus comprises: a
first wavelength-selective coupler having a first coupler first
side and a first coupler second side, wherein the first coupler
first side further comprising a first coupler optical pump input
port coupled to an optical pump, and a first coupler signal output
port adapted to output a first amplified optical sensor signal, and
the first coupler second side having a first coupler optical
amplifier connection port. The apparatus further comprises a first
optical amplifier having a first amplifier first port and a first
amplifier second port, wherein the first amplifier first port is
coupled to the first coupler optical amplifier connection port, and
the first amplifier second port adapted to receive a first optical
sensor signal input. The apparatus further still comprises a second
wavelength-selective coupler having a second coupler first side and
a second coupler second side, wherein the second coupler first side
further comprising a second coupler optical pump input port coupled
to the optical pump, and a second coupler signal output port
adapted to output a second amplified optical sensor signal, and the
second coupler second side having a second coupler optical
amplifier connection port; and a second optical amplifier having a
second amplifier first port and a second amplifier second port,
wherein the second amplifier first port is coupled to the second
coupler optical amplifier connection port, and the second amplifier
second port adapted to receive a second optical sensor signal
input, wherein a second amplified optical sensor signal
results.
[0011] In a still another aspect of the invention, a method of
amplifying optical sensor signals is provided. The method comprises
pumping a first optical amplifier, located in a seismic cable, with
a pumping source, and feeding a first optical signal to the first
optical amplifier. The method further comprises pumping a second
optical amplifier, located in the seismic cable, with the same
pumping source, and feeding a second optical signal to the second
optical amplifier.
[0012] In another aspect of the invention, a system for amplifying
optical sensor signals is provided. The system comprises a means
for pumping a first optical amplifier, located in a seismic cable,
with a pumping source, and a means for feeding a first optical
signal to the first optical amplifier. The system further comprises
a means for pumping a second optical amplifier, located in the
seismic cable, with the same pumping source, and a means for
feeding a second optical signal to the second optical
amplifier.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 shows an example embodiment of the present invention
for an apparatus having remote optical signal amplification in a
series configuration.
[0014] FIG. 2 shows an example embodiment of the present invention
for an apparatus having remote multistage optical signal
amplification.
[0015] FIG. 3 shows an example embodiment of the present invention
for an apparatus having remote optical signal amplification in
parallel configuration.
[0016] FIG. 4 shows example embodiments of the present invention
for systems involving amplifying optical sensor signals with the
same pump source.
[0017] FIG. 5 shows example embodiments of the present invention
for systems involving amplifying optical sensor signals with
telemetry lines feeding optical signals from seismic arrays to
optical amplifiers.
[0018] FIG. 6 shows example embodiments of the present invention
for systems involving splitting a pump signal before amplifying
optical sensor signals with the same pump source.
[0019] FIG. 7 shows example embodiments of the present invention
for systems involving feeding optical signals through separate
lines to optical amplifiers, that is, a one to one ratio between
lines and amplifiers.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0020] Referring now to FIG. 1, an example embodiment of the
invention is seen in which an apparatus 10 for remote amplification
of at least one optical sensor signal 15 is provided. Applications
of embodiments include seismic sensing, down-hole logging, and many
other applications as will occur to those of skill in the art.
According to the illustrated embodiment, the apparatus 10 comprises
at least one amplification section 20, wherein the at least one
amplification section 20 comprises: a first wavelength-selective
coupler 25 having a first coupler first side 30 and a first coupler
second side 35, the first coupler first side 30 further comprising
an optical pump input port 40, adapted to receive an optical pump
input 45, and a signal output port 50 adapted to output an
amplified optical sensor signal 55. The first coupler second side
35 includes a first coupler optical amplifier connection port 60
and an optical amplifier 65 having an amplifier first port 70 and
an amplifier second port 75, wherein the amplifier first port 70 is
coupled to the first coupler optical amplifier connection port 60.
A second wavelength-selective coupler 80 is also seen, having a
second coupler first side 85 and a second coupler second side 90.
The second coupler first side 85 is optically coupled to the
amplifier second port 75.
[0021] The second coupler second side 90 further comprises a second
coupler signal input port 95 and an optical pump tap out port 100,
wherein the second coupler signal input port 95 is adapted to
receive at least one optical sensor signal 15 inputs, and the
optical pump tap out port 100 is adapted to output an excess
optical pump energy 105 to another amplification section 110.
[0022] Still referring to the example embodiment of FIG. 1, the at
least one amplification section 20 comprises a plurality of
amplification sections coupled to each other in a cascaded manner,
wherein each amplification section 20 is adapted to receive one
optical sensor signal input 15, output one optical sensor signal
output 55, and output one excess optical pump energy 105 to an
adjacent amplification section 110. In another embodiment, the
first wavelength-selective coupler 25 comprises a WDM coupler. In a
still another embodiment, the second wavelength-selective coupler
80 comprises a WDM coupler. In a still further embodiment, the
optical amplifier 65 comprises an erbium doped optical amplifier.
In a yet another embodiment, the second coupler signal input port
further comprises an optical isolator 115. In a still another
embodiment, the optical isolator 115 is integral to the second
coupler signal input port 95.
[0023] In additional specific embodiments, the excess optical pump
energy 105 is used to provide optical pump energy to the optical
pump input port of a next amplification section 110. Similarly, the
process of providing left over optical pump energy to the adjacent
amplification section is continued. Design of the apparatus 10
provides unique advantage of modular construction of seismic sensor
arrays in which the amplification sections are connected serially
according to the requirements in the field and provided with remote
optical pumping from a single optical pump.
[0024] Now referring to FIG. 2, another example embodiment of the
invention is seen in which an apparatus 200 is provided for remote
multistage amplification of a optical sensor signal 210. According
to the illustrated embodiment, the apparatus 200 comprises: a first
wavelength-selective coupler 215 having a first coupler first side
220 and a first coupler second side 225, wherein the first coupler
first side 220 further comprises a first coupler optical pump input
port 230 adapted to receive an optical pump input 235, and a first
coupler signal output port 240 adapted to output an amplified
optical sensor signal 245. The first coupler second side 225
includes a first coupler optical amplifier connection port 250 and
a first optical amplifier 255, having a first amplifier first port
260 and a first amplifier second port 265, wherein the first
amplifier first port 260 is coupled to the first coupler optical
amplifier connection port 250. A second wavelength-selective
coupler 270 is provided having a second coupler first side 275 and
a second coupler second side 280, wherein the second coupler first
side 275 is optically coupled to the first amplifier second port
265. The second coupler second side 280 further comprises a second
coupler signal input port 285 and a second coupler optical pump
output port 290, wherein the second coupler signal input port 285
is adapted to receive an amplified optical sensor signal 295 input.
Further, the second coupler optical pump output port 290 is adapted
to output a first excess optical pump energy 300. A third
wavelength-selective coupler 305 includes a third coupler first
side 310 and a third coupler second side 315, wherein the third
coupler first side 310 further comprises a third coupler signal
output port 320, and a third coupler optical pump energy input port
325. The third coupler optical pump energy input port 325 is
optically coupled to the second coupler optical pump output port
290, and the third coupler second side 315 further comprises a
third coupler signal input port 330. A second optical amplifier 335
is provided and includes a second amplifier first port 340 and a
second amplifier second port 345, wherein the second amplifier
first port 340 is coupled to the third coupler signal input port
330. Fourth wavelength-selective coupler 350 has a fourth coupler
first side 355 and a fourth coupler second side 360, wherein the
fourth coupler first side 355 is optically coupled to the second
amplifier second port 345, and the fourth coupler second side 360
further comprises a fourth coupler signal input port 365 and a
fourth coupler optical pump output port 370. The fourth coupler
signal input port 365 is adapted to receive a optical sensor signal
210 input, and the fourth coupler optical pump output port 370 is
adapted to output a second excess optical pump energy 375.
[0025] Again referring to FIG. 2, in one of the embodiments of the
invention, the first wavelength-selective coupler 215 comprises a
WDM coupler. In another embodiment, the first optical amplifier
comprises 255 an erbium doped optical amplifier. In a still another
embodiment, the second wavelength-selective coupler 270 comprises a
WDM coupler. In a still further embodiment, the second coupler
signal input port 285 further comprises a first optical isolator
380. In a yet still further embodiment, the first optical isolator
380 is integral to the second coupler signal input port 285. In a
yet further embodiment, the third wavelength-selective coupler 305
comprises a WDM coupler. In a still other embodiment, the second
optical amplifier 335 comprises an erbium doped optical amplifier.
In another aspect of the embodiment, the fourth
wavelength-selective coupler 350 comprises a WDM coupler. In a yet
another aspect of the embodiment, the fourth coupler signal input
port 365 further comprises a second optical isolator 385. In a
still yet another aspect of the embodiment, the second optical
isolator 385 is integral to the fourth coupler signal input port
365.
[0026] Note that the second excess optical pump energy 375 is used,
in some embodiments, to provide optical pump energy to the optical
pump input port of a next signal amplification module that is
similar to the apparatus 200. Likewise, the process of providing
left over optical pump energy to the adjacent amplification module
that is similar to the apparatus 200 is continued in other
embodiments. Design of the apparatus 200 provides unique advantage
of modular construction of seismic sensor arrays in which the
amplification modules can be connected serially according to the
requirements in the field and provided with remote optical pumping
from a single optical pump.
[0027] Referring now to FIG. 3, another example embodiment of the
apparatus 400 for remote amplification of a plurality of optical
sensor signals 410 and 415 in a parallel configuration using an
optical pump 420 is seen. Here, the apparatus 400 comprises: a
first wavelength-selective coupler 425 having a first coupler first
side 430 and a first coupler second side 435, wherein the first
coupler first side 430 further comprises a first coupler optical
pump input port 440 coupled to an optical pump 420, and a first
coupler signal output port 445 adapted to output a first amplified
optical sensor signal 450. The first coupler second side 435 has a
first coupler optical amplifier connection port 450. First optical
amplifier 455 includes a first amplifier first port 460 and a first
amplifier second port 465, wherein the first amplifier first port
460 is coupled to the first coupler optical amplifier connection
port 450, and the first amplifier second port 465 adapted to
receive a first optical sensor signal 410 input. Second
wavelength-selective coupler 470 comprises a second coupler first
side 475 and a second coupler second side 480, wherein the second
coupler first side 475 further comprises a second coupler optical
pump input port 485 coupled to the optical pump 420, and a second
coupler signal output port 490 adapted to output a second amplified
optical sensor signal 495, and the second coupler second side 480
has a second coupler optical amplifier connection port 500. Second
optical amplifier 505 includes a second amplifier first port 510
and a second amplifier second port 515, wherein the second
amplifier first port 510 is coupled to the second coupler optical
amplifier connection port 500, and the second amplifier second port
515 adapted to receive a second optical sensor signal 415
input.
[0028] Referring still to FIG. 3, in one embodiment of the
invention, the first wavelength-selective coupler 425 comprises a
WDM coupler. In another embodiment, the first optical amplifier 455
comprises an erbium doped optical amplifier. In a yet another
embodiment, the first amplifier second port 465 further comprises a
first optical isolator 520. In a still yet another embodiment, the
first optical isolator 520 is integral to the first amplifier
second port 465. In a further yet another embodiment, the second
wavelength-selective coupler 470 comprises a WDM coupler. In a
still another embodiment, the second optical amplifier 505
comprises an erbium doped optical amplifier. In another aspect of
the embodiment, the second amplifier second port 515 further
comprises a second optical isolator 525. In a still another aspect
of the embodiment, the second optical isolator 525 is integral to
the second amplifier second port 515.
[0029] Note that in embodiments of FIG. 3, any number of branches,
within the of capabilities of the hardware used, are arranged in a
parallel configuration to remotely amplify optical sensor signals
using a single optical pump, wherein branches in the parallel
configuration provide a modular structure of the apparatus 400.
[0030] Referring now to FIG. 4, further example embodiments of the
invention are depicted, wherein a system 600 for amplifying optical
sensor signals 610a, 610b is disclosed. The system 600 comprises a
means 620 for pumping a first optical amplifier 622a, located in a
seismic cable 605, with a pumping source 615, and a means 625 for
feeding a first optical signal 610a to the first optical amplifier
622a. The system 600 further comprises a means 630 for pumping a
second optical amplifier 622b, located in the seismic cable 605,
with the pumping source 615, and a means 635 for feeding a second
optical signal 610b to the second optical amplifier 622b. The
pumping of the optical amplifiers 622a, 622b with a pump signal 622
from the pump source 615 shared by all optical amplifiers 622a,
622b excites the ions in the optical amplifiers 622a, 622b.
Typically, the ions are erbium ions in the doped fiber coils of the
optical amplifiers 622a, 622b, and the pump source 615 exciting
these erbium ions is sent through cabling, telemetry lines, or the
like, as is seen in FIG. 5.
[0031] Turning to FIG. 5 then, another example embodiment of the
invention is the system 600 previously described, wherein the means
(FIG. 4, reference 625) for feeding the first optical signal 610a
comprises means for feeding the first optical signal 610a through a
first telemetry line 642, and the means (FIG. 4, reference 635) for
feeding the second optical signal 610b comprises feeding the second
optical signal 610b through a second telemetry line 652. Other
methods and means for feeding optical signals will occur to those
of skill in the art that do not depart from the spirit of the
claimed invention.
[0032] Referring to FIG. 6, another example embodiment of the
invention is the system 600 previously described and further
comprising a means 660 for splitting a pump signal 662 from the
pumping source 615 before the means 620 for pumping the first
optical amplifiers 622a and before the means 630 for pumping the
second optical amplifier 622b. Rather than using the described
method and system in a series configuration, whether a cascading or
in-line series configuration, splitting the pump signal 662 is
ideal for use of the disclosed methods and systems in a parallel
configuration. Joining two separate telemetry lines (642, 652 on
FIG. 5), wherein each telemetry line (642, 652 on FIG. 5) has its
own input optical signals (610a, 610b on FIG. 5), is a coupler,
such as a WDM coupler. But even before the WDM coupler, a pump
demultiplexer 660 splits out the pump signal 662 from the same pump
source 615 so that each telemetry line 620, 630 has its own pump
signal 662 to excite an optical amplifier 622a, 622b, and thereby,
produce amplified optical signals.
[0033] Turning back to FIG. 5, another example embodiment of the
invention is seen, wherein the system 600 further comprises a means
670 for receiving the first optical signal 610a from a first
seismic sensor array 672, and means 675 for receiving the second
optical signal 610b from a second seismic sensor array 678. For
example, methods and means 670, 675 for receiving optical signals
610a, 610b from arrays 672, 678 include through cabling, lines or
the like.
[0034] Referring to FIG. 4 again, more example embodiments of the
invention are shown. In one example embodiment, the system 600
further comprises a means 680 for pumping additional optical
amplifiers 622 with the pumping source 615. That is, the previously
described methods and systems are not limited to two optical
amplifiers 622a, 622b, two optical signals 610a, 610b, and so
forth. Rather, the invention is remote amplification of many
optical signals 610 using the same pump source 615 for multiple
amplifiers 622. In still another example embodiment, the system 600
further comprises a means 690 for feeding additional optical
signals 610 to additional optical amplifiers 622. And in FIG. 7,
another example embodiment is illustrated, wherein the means (690
on FIG. 4) for feeding additional optical signals 610 comprises
through separate telemetry lines 705. That is, for example, a
method or system employing twenty optical amplifiers 622, then
twenty telemetry lines 705 are used wherein each telemetry line 705
is connected to its own optical amplifier 622, feeds its own
optical amplifier 622, but all twenty optical amplifiers 622 share
the same pump source (615 on FIG. 4) for exciting the fibers of the
optical amplifiers 622.
[0035] The various means described in reference to the later
Figures will be understood and will occur to those of ordinary
skill in the art from a review of the earlier disclosure, and the
specific examples of the various drawings.
[0036] Having thus described exemplary embodiments of the
invention, it will be apparent that various alterations,
modifications and improvements will readily occur to those skilled
in the art. Such obvious alterations, modifications and
improvements, though not expressly described above, are
nevertheless intended to be implied and are within the spirit and
scope of the invention. Accordingly, the foregoing discussion is
intended to be illustrative only, and not limiting; the invention
is limited and defined by the following claims and equivalents
thereto.
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